Antenatal glucocorticoids blunt the functioning of the hypothalamic-pituitary-adrenal axis of neonates and disturb some behaviors in juveniles

Gestational administration of vitamin D improves maternal care and prevents anxiety-like behavior in male and female Wistar rats prenatally exposed to dexamethasone

Prenatal overexposure to glucocorticoids (GC) can lead to behavioral changes in adulthood. We aimed to explore the effects of gestational administration of vitamin D on the behavioral responses of dams and their offspring prenatally exposed to dexamethasone (DEX). Vitamin D (500UI) was given daily during the whole pregnancy (VD group). Half of the groups that received vitamin D were treated with DEX (0.1 mg/kg, VD + DEX group) daily between the 14th and 19th days of pregnancy. The corresponding control groups of progenitors were assigned (CTL and DEX groups, respectively). Maternal care and the dam's behaviors were evaluated during lactation. The offspring had developmental and behavioral parameters evaluated during lactation and at 3, 6, and 12 months of age. Gestational administration of vitamin D increased maternal care and had an anxiolytic-like effect on the dams, but the latter was blocked in DEX-treated dams. Prenatal DEX partially impaired neural development and caused an anxiety-like phenotype in the male and female offspring at 6 months, which was prevented by gestational administration of vitamin D. As well, gestational vitamin D improved memory just in the male offspring, but this response was suppressed by prenatal DEX. We concluded that gestational vitamin D could prevent anxiety-like behavior in adult male and female rats prenatally exposed to DEX, which might be, in part, a result of the maternal care improvement.

Antenatal low-intensity pulsed ultrasound reduces neurobehavioral deficits and brain injury following dexamethasone-induced intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a leading cause of perinatal mortality and morbidity, and IUGR survivors are at increased risk of neurodevelopmental deficits. No effective interventions are currently available to improve the structure and function of the IUGR brain before birth. This study investigated the protective effects of low‐intensity pulsed ultrasound (LIPUS) on postnatal neurodevelopmental outcomes and brain injury using a rat model of IUGR induced by maternal exposure to dexamethasone (DEX). Pregnant rats were treated with DEX (200 μg/kg, s.c.) and LIPUS daily from gestational day (GD) 14 to 19. Behavioral assessments were performed on the IUGR offspring to examine neurological function. Neuropathology, levels of neurotrophic factors, and CaMKII‐Akt‐related molecules were assessed in the IUGR brain, and expression of glucose and amino acid transporters and neurotrophic factors were examined in the placenta. Maternal LIPUS treatment increased fetal weight, fetal liver weight, and placental weight following IUGR. LIPUS treatment also increased neuronal number and myelin protein expression in the IUGR brain, and attenuated neurodevelopmental deficits at postnatal day (PND) 18. However, the number of oligodendrocytes or microglia was not affected. These changes were associated with the upregulation of brain‐derived neurotrophic factor (BDNF) and placental growth factor (PlGF) protein expression, and enhancement of neuronal CaMKII and Akt activation in the IUGR brain at PND 1. Additionally, LIPUS treatment promoted glucose transporter (GLUT) 1 production and BDNF expression in the placenta, but had no effects on GLUT3 or amino acid transporter expression. Our findings suggest that antenatal LIPUS treatment may reduce IUGR‐induced brain injury via enhancing cerebral BDNF/CaMKII/Akt signaling. These data provide new evidence that LIPUS stimulation could be considered for antenatal neuroprotective therapy in IUGR.

Long-term neuropathological and/or neurobehavioral effects of antenatal corticosteroid therapy in animal models: a systematic review

BACKGROUND

Antenatal corticosteroids (ACSs) are recommended to all women at risk for preterm delivery; currently, there is controversy about the subsequent long-term neurocognitive sequelae. This systematic review summarizes the long-term neurodevelopmental outcomes after ACS therapy in animal models.

METHODS

An electronic search strategy incorporating MeSH and keywords was performed using all known literature databases and in accordance with PRISMA guidance (PROSPERO CRD42019119663).

RESULTS

Of the 669 studies identified, eventually 64 were included. The majority of studies utilized dexamethasone at relative high dosages and primarily involved rodents. There was a high risk of bias, mostly due to lack of randomization, allocation concealment, and blinding. The main outcomes reported on was neuropathological, particularly glucocorticoid receptor expression and neuron densities, and neurobehavior. Overall there was an upregulation of glucocorticoid receptors with lower neuron densities and a dysregulation of the dopaminergic and serotonergic systems. This coincided with various adverse neurobehavioral outcomes.

CONCLUSIONS

In animal models, ACSs consistently lead to deleterious long-term neurocognitive effects. This may be due to the specific agents, i.e., dexamethasone, or the repetitive/higher total dosing used. ACS administration varied significantly between studies and there was a high risk of bias. Future research should be standardized in well-characterized models.

Maternal exercise increases but concurrent maternal fluoxetine prevents the increase in hippocampal neurogenesis of adult offspring

Treating postpartum depression (PPD) with pharmacological antidepressants like fluoxetine (FLX) is complicated because these drugs can remain active in breast milk and potentially affect infant development. Alternatively, non-pharmacological treatments such as exercise are associated with beneficial effects on infant development but its potential ability to counter the effects of PPD are largely unknown. To investigate this, we treated dams with corticosterone (CORT) or vehicle (sesame oil) from postpartum days 2-25 to model PPD. Within oil and CORT treatments, dams were also assigned to one of these treatments: 1) exercise (voluntary running wheel) + FLX (10 mg/kg, i.p.), 2) exercise + saline (vehicle for FLX), 3) no exercise + FLX, 4) no exercise + saline. Both male and female offspring were analyzed, and this generated a total of 16 experimental groups for this study. Adult male and female offspring (125 d old) of these dams were tested for anxiety-like behavior in the novelty suppressed feeding test and stress reactivity in the dexamethasone suppression test. Hippocampal tissue was processed for doublecortin, a protein expressed in immature neurons. Regardless of sex, maternal exercise increased neurogenesis in the dorsal hippocampus of adult offspring, but concurrent exposure to maternal fluoxetine prevented this effect. Exposure to either maternal exercise or maternal FLX facilitated HPA negative feedback in adult males but not females. Maternal postpartum CORT also facilitated HPA feedback in adult offspring of both sexes. Collectively, these data indicate that maternal exercise increased dorsal hippocampal neurogenesis in both sexes but differentially affected offspring HPA axis based on sex. Alternatively, maternal postpartum FLX facilitated HPA axis negative feedback only in males. These findings indicate that different types of maternal interventions bear long-term effects on offspring outcome with implications for treating PPD.

Influence of antenatal synthetic glucocorticoid administration on pyramidal cell morphology and microtubule-associated protein type 2 (MAP2) in rat cerebrocortical neurons

Previous animal studies have indicated that excessive prenatal circulating glucocorticoid (GC) levels induced by the antenatal administration of synthetic GC (sGC) significantly alter neuronal development in the cerebellar and hippocampal neurons of the offspring. However, it is unknown whether antenatal sGC administration results in long-term neocortical pyramidal cell impairment. In the current study, we examined whether an equivalent therapeutic dose of antenatal betamethasone phosphate (BET) in pregnant rats alters the Golgi-stained basilar dendritic length and histochemical expression of dendritic microtubule-associated protein 2 (MAP2) of neocortical pyramidal cells in infant, adolescent, and young adult offspring. The results obtained showed that in utero BET exposure resulted in a significant reduction in the basilar dendritic length per neuron and a transient reduction in histochemical MAP2 immunoreactivity. Consistent with previous hippocampal and cerebellar data, the present findings suggest that prenatal BET administration alters the dendritic growth of cerebrocortical pyramidal cells.

Effects of Antenatal Corticosteroids on Cortisol and Heart Rate Reactivity of Preterm Infants

Administration of glucocorticoids (GCs) during pregnancy is an established practice for reducing morbidity and mortality of fetuses at risk of preterm delivery. However, preliminary research indicates that exposure to exogenous GCs in utero may be associated with suppressed hypothalamic–pituitary–adrenal axis activity. The aim of this study was to determine whether preterm neonates who are exposed to antenatal corticosteroids show evidence of a suppressed stress-response system during their first few weeks of life, in contrast to infants who are not exposed. The sample (51% female) included 57 neonates, with 74% exposed to steroids. Mean gestational ages (GAs) were 32.6 weeks for exposed and 34.7 weeks for nonexposed infants. Although neonates in the two groups differed in gender, birth weight, and morbidity, these factors were controlled for in data analyses. Infants’ salivary cortisol and heart rate (HR) were measured before and after they received a standardized caregiving “stressor” while in the newborn intensive care unit. Infants exposed to GCs in utero had lower basal cortisol levels and higher HRs than their nonexposed peers. In contrast to infants who received no GCs, they also exhibited minimal HR or cortisol reactivity to the stressor. Findings suggest that preterm infants who were exposed to antenatal corticosteroids experience a suppressed response to stress. As preterm children develop, this dysregulation has numerous implications for later development of stress-related cardiovascular and mental health problems. Further research is needed to determine whether these postnatal effects of antenatal corticosteroids persist over time.

Perinatal dexamethasone-induced alterations in apoptosis within the hippocampus and paraventricular nucleus of the hypothalamus are influenced by age and sex

Exposure to high levels of glucocorticoids (GCs) during development leads to long-term changes in hypothalamic-pituitary-adrenal (HPA) axis regulation, although little is known about the neural mechanisms that underlie these alterations. In this study, we investigated the effects of late gestational (days 18-22) or postnatal (days 4-6) administration of the GC receptor agonist dexamethasone (DEX) on an apoptosis marker in two brain regions critical to HPA axis regulation, the hippocampus and the hypothalamic paraventricular nucleus (PVN). One day after the final DEX injection, male and female rats were sacrificed, and brains were processed for immunohistochemical detection of cleaved caspase-3, an apoptotic cell death indicator. DEX increased cleaved caspase-3 immunoreactivity in the CA1 hippocampal region of both sexes following prenatal but not postnatal treatment. Prenatal DEX also increased caspase-3 immunoreactivity in the CA3 region, an elevation that tended to be greater in females. In contrast, postnatal DEX resulted in a much smaller, albeit significant, induction in CA3 caspase-3 compared with prenatal treatment. Quantitative real-time PCR analysis revealed that prenatal but not postnatal DEX-induced hippocampal cleaved caspase-3 correlated with elevated mRNA of the proapoptotic gene Bad. Few caspase-3-ir cells were identified within the PVN regardless of treatment age, although postnatal but not prenatal DEX increased this number. However, the region immediately surrounding the PVN (peri-PVN) showed significant increases in caspase-3-ir cells following pre- and postnatal DEX. Together these findings indicate that developmental GC exposure increases apoptosis in HPAaxis-associated brain regions in an age- and sex-dependent manner.

Transcriptomic and epigenetic changes in the hypothalamus are involved in an increased susceptibility to a high-fat-sucrose diet in prenatally stressed female rats

Disturbances in the prenatal period are linked to metabolic disorders in adulthood, implying the hypothalamic systems of appetite and energy balance regulation. In order to analyze the central effects of a high-fat-sucrose (HFS) diet in prenatally stressed (PNS) female adult rats, Wistar dams were exposed to chronic-mild-stress during the third week of gestation and were then compared with unstressed controls. Adult female offspring were fed a chow or HFS diet for 10 weeks. Changes in body weight, adiposity as well as expression and methylation levels of selected hypothalamic genes were analyzed. PNS induced lower birthweight and body length with no changes in body fat mass. After the HFS diet, the expected overweight model was observed accompanied by higher adiposity and insulin resistance, which was worsened by PNS. The stress model induced higher energy intake in adulthood. Hypothalamic gene expression analysis revealed that the HFS diet decreased Slc6a3 (dopamine active transporter), NPY (neuropeptide Y) and IR (insulin receptor) and increased POMC (pro-opiomelanocortin). Hypothalamic DNA methylation levels in the promoter region of Slc6a3 revealed that Slc6a3 was hypermethylated by the HFS diet in CpG site -53 bp to the transcription start site. HFS diet also hypermethylated CpG site -167 bp of the POMC promoter only in nonstressed animals. No correlations were found between gene expression and DNA methylation levels. These results imply that early-life stress in females increased predisposition to diet-induced obesity in adulthood.

Repeated antenatal corticosteroid treatments adversely affect neural transmission time and auditory thresholds in laboratory rats

Antenatal corticosteroid (AC) treatment is given to pregnant women at risk for preterm birth to reduce infant morbidity and mortality by enhancing lung and brain maturation. However, there is no accepted regimen on how frequently AC treatments should be given and some studies found that repeated AC treatments can cause growth retardation and brain damage. Our goal was to assess the dose-dependent effects of repeated AC treatment and estimate the critical number of AC courses to cause harmful effects on the auditory brainstem response (ABR), a sensitive measure of brain development, neural transmission and hearing loss. We hypothesized that repeated AC treatment would have harmful effects on the offspring's ABRs and growth only if more than 3 AC treatment courses were given. To test this hypothesis, pregnant Wistar rats were given either a high regimen of AC (HAC), a moderate regimen (MAC), a low regimen (LAC), or saline (SAL). An untreated control (CON) group was also used. Simulating the clinical condition, the HAC dams received 0.2mg/kg Betamethasone (IM) twice daily for 6 days during gestation days (GD) 17-22. The MAC dams received 3 days of AC treatment followed by 3 days of saline treatment on GD 17-19 and GD 20-22, respectively. The LAC dams received 1 day of AC treatment followed by 5 days of saline treatment on GD 17 and GD 18-22, respectively. The SAL dams received 6 days of saline treatment from GD 17 to 22 (twice daily, isovolumetric to the HAC injections, IM). The offspring were ABR-tested on postnatal day 24. Results indicated that the ABR's P4 latencies (neural transmission time) were significantly prolonged (worse) in the HAC pups and that ABR's thresholds were significantly elevated (worse) in the HAC and MAC pups when compared to the CON pups. The HAC and MAC pups were also growth retarded and had higher postnatal mortality than the CON pups. The SAL and LAC pups showed little or no adverse effects. In conclusion, repeated AC treatment had harmful effects on the rat offspring's ABRs, postnatal growth and survival. The prolonged ABR latencies reflect slowed neural transmission times along the auditory nerve and brainstem auditory pathway. The elevated ABR thresholds reflect hearing deficits. We concluded that repeated AC treatment can have harmful neurological, sensory and developmental effects on the rat offspring. These effects should be considered when weighing the benefits and risks of repeated AC treatment and when monitoring and managing the prenatally exposed child for possible adverse effects.

Effect of fish oil and coconut fat supplementation on depressive-type behavior and corticosterone levels of prenatally stressed male rats

Prenatal stress (PNS) during critical periods of brain development has been associated with numerous behavioral and/or mood disorders in later life. These outcomes may result from changes in the hypothalamic-pituitary-adrenal (HPA) axis activity, which, in turn, can be modulated by environmental factors, such as nutritional status. In this study, the adult male offspring of dams exposed to restraint stress during the last semester of pregnancy and fed different diets were evaluated for depressive-like behavior in the forced swimming test and for the corticosterone response to the test. Female Wistar rats were allocated to one of three groups: regular diet, diet supplemented with coconut fat or with fish oil, offered during pregnancy and lactation. When pregnancy was confirmed, they were distributed into control or stress groups. Stress consisted of restraint and bright light for 45 min, three times per day, in the last week of pregnancy. The body weight of the adult offspring submitted to PNS was lower than that of controls. In the forced swimming test, time of immobility was reduced and swimming was increased in PNS rats fed fish oil and plasma corticosterone levels immediately after the forced swimming test were lower in PNS rats fed regular diet than their control counterparts; this response was reduced in control rats whose mothers were fed fish oil and coconut fat. The present results indicate that coconut fat and fish oil influenced behavioral and hormonal responses to the forced swimming test in both control and PNS adult male rats.

Comparative analysis of maternal care in the high-yawning (HY) and low-yawning (LY) sublines from Sprague-Dawley rats

High- and low-yawning rats (HY and LY) were selectively bred as a function of their spontaneous yawning frequency with the LY subline about 2 yawns/hr and the HY 20 yawns/hr. The HY rats have more grooming bouts and travel longer distances in an open field. HY dams spent less time in the nest, retrieved their pups faster, and show a longer latency to licking and mouthing the pups than the LY or outbred Sprague-Dawley (SD) animals. The percentage of HY dams that had atypical retrieving was higher, with a lower nest quality, and produced offspring whose weights were lower than those from the LY subline. We also showed that the pregnant HY dams have fewer pups and the percentage that had lost at least three pups during lactation was higher than the SD and LY dams. In conclusion, HY dams are motivated to take care of their pups, but the "fine tuning" of maternal care is disturbed.

Effects of intrauterine exposure to synthetic glucocorticoids on fetal, newborn, and infant hypothalamic-pituitary-adrenal axis function in humans: a systematic review

BACKGROUND

Synthetic glucocorticoids are commonly used in reproductive medicine. Fetal organ systems are highly sensitive to changes in the intrauterine environment, including overexposure to glucocorticoids. Structural and functional alterations resulting from such changes may persist throughout life and have been associated with diverse diseases. One system that could be particularly sensitive to fetal glucocorticoid overexposure is the hypothalamic-pituitary-adrenal (hpa) axis. Many human studies have investigated this possibility, but a systematic review to identify consistent, emergent findings is lacking.

METHODS

We systematically review 49 human studies, assessing the effects of intrauterine exposure to synthetic glucocorticoids on fetal, neonate, and infant hpa function.

RESULTS

Study quality varied considerably, but the main findings held true after restricting the analyses to higher-quality studies: intrauterine exposure to synthetic glucocorticoids reduces offspring hpa activity under unstimulated conditions after pain but not pharmacological challenge. Although reduced unstimulated hpa function appears to recover within the first 2 wk postpartum, blunted hpa reactivity to pain is likely to persist throughout the first 4 months of life. There is some evidence that the magnitude of the effects is correlated with the total amount of glucocorticoids administered and varies with the time interval between glucocorticoid exposure and hpa assessment.

CONCLUSIONS

This systematic review has allowed the demonstration of the way in which intrauterine exposure to various regimens of synthetic glucocorticoids affects various forms of hpa function. As such, it guides future studies in terms of which variables need to be focused on in order to further strengthen the understanding of such therapy, whilst continuing to profit from its clinical benefits.

Effects of prenatal dexamethasone treatment on physical growth, pituitary-adrenal hormones, and performance of motor, motivational, and cognitive tasks in juvenile and adolescent common marmoset monkeys

Synthetic glucocorticoids such as dexamethasone (DEX) are commonly used to prevent respiratory distress syndrome in preterm infants, but there is emerging evidence of subsequent neurobehavioral abnormalities (e.g. problems with inattention/hyperactivity). In the present study, we exposed pregnant common marmosets (Callithrix jacchus, primates) to daily repeated DEX (5 mg/kg by mouth) during either early (d 42-48) or late (d 90-96) pregnancy (gestation period of 144 days). Relative to control, and with a longitudinal design, we investigated DEX effects in offspring in terms of physical growth, plasma ACTH and cortisol titers, social and maintenance behaviors, skilled motor reaching, motivation for palatable reward, and learning between infancy and adolescence. Early DEX resulted in reduced sociability in infants and increased motivation for palatable reward in adolescents. Late DEX resulted in a mild transient increase in knee-heel length in infants and enhanced reversal learning of stimulus-reward association in adolescents. There was no effect of either early or late DEX on basal plasma ACTH or cortisol titers. Both treatments resulted in impaired skilled motor reaching in juveniles, which attenuated in early DEX but persisted in late DEX across test sessions. The increased palatable-reward motivation and decreased social motivation observed in early DEX subjects provide experimental support for the clinical reports that prenatal glucocorticoid treatment impairs social development and predisposes to metabolic syndrome. These novel primate findings indicate that fetal glucocorticoid overexposure can lead to abnormal development of motor, affective, and cognitive behaviors. Importantly, the outcome is highly dependent upon the timing of glucocorticoid overexposure.

Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence

Prenatal maternal stress (PNMS) has been linked with adverse health outcomes in the offspring through experimental studies using animal models and epidemiological studies of human populations. The purpose of this review article is to establish a parallel between animal and human studies, while focusing on methodological issues and gaps in knowledge. The review examines the quality of recent evidence for prevailing PNMS theoretical models, namely the biopsychosocial model for adverse pregnancy outcomes and the fetal programming model for chronic diseases. The investigators used PubMed (2000-06) to identify recently published original articles in the English language literature. A total of 103 (60 human and 43 animal) studies were examined. Most human studies originated from developed countries, thus limiting generalisability to developing nations. Most animal studies were conducted on non-primates, rendering extrapolation of findings to pregnant women less straightforward. PNMS definition and measurement were heterogeneous across studies examining similar research questions, thus precluding the conduct of meta-analyses. In human studies, physical health outcomes were often restricted to birth complications while mental health outcomes included postnatal developmental disorders and psychiatric conditions in children, adolescents and adults. Diverse health outcomes were considered in animal studies, some being useful models for depression, schizophrenia or attention deficit hyperactivity disorder in human populations. The overall evidence is consistent with independent effects of PNMS on perinatal and postnatal outcomes. Intervention studies and large population-based cohort studies combining repeated multi-dimensional and standardised PNMS measurements with biomarkers of stress are needed to further understand PNMS aetiology and pathophysiology in human populations.

Neuroendocrine disorders in adult rats treated prenatally with hydrocortisone acetate

We investigated the effects of hydrocortisone acetate administered to pregnant rats over the last gestational week on some neuroendocrine characteristics in adult female and male offspring. Prenatal glucocorticoid eliminated sex dimorphism of the neurons nuclei volumes in the medial preoptic area and the suprachiasmatic nuclei. There was no elevation of blood plasma corticosterone level after noradrenaline infusion into the third brain ventricle in experimental males; meanwhile, in females adrenocortical response was augmented. Male offspring exhibited a decrease of plasma corticosterone response to an acute stress (1h restraint) that was not accompanied by post-stress changes neither in the hypothalamic noradrenaline content nor hippocampal glutamate decarboxylase activity. On the contrary, moderate augmentation of adrenocortical stress reactivity and inhibitory effect of GABAergic system were found in females. It was concluded that exposure to prenatal glucocorticoid is able to alter development of the neuroendocrine systems related to reproduction and stress responses both in males and females and resulted in modification of its sex-dimorphic features in adult life.

The primary headaches: genetics, epigenetics and a behavioural genetic model

The primary headaches, migraine with (MA) and without aura (MO) and cluster headache, all carry a substantial genetic liability. Familial hemiplegic migraine (FHM), an autosomal dominant mendelian disorder classified as a subtype of MA, is due to mutations in genes encoding neural channel subunits. MA/MO are considered multifactorial genetic disorders, and FHM has been proposed as a model for migraine aetiology. However, a review of the genetic studies suggests that the FHM genes are not involved in the typical migraines and that FHM should be considered as a syndromic migraine rather than a subtype of MA. Adopting the concept of syndromic migraine could be useful in understanding migraine pathogenesis. We hypothesise that epigenetic mechanisms play an important role in headache pathogenesis. A behavioural model is proposed, whereby the primary headaches are construed as behaviours, not symptoms, evolutionarily conserved for their adaptive value and engendered out of a genetic repertoire by a network of pattern generators present in the brain and signalling homeostatic imbalance. This behavioural model could be incorporated into migraine genetic research.

Fetal programming of hypothalamic-pituitary-adrenal (HPA) axis function and behavior by synthetic glucocorticoids

Reduced fetal growth has been closely associated with an increased risk for the development of chronic disease in later life. Accumulating evidence indicates that fetal exposure to excess glucocorticoids represents a critical mechanism underlying this association. Approximately 7% of pregnant women are at risk of preterm delivery and these women are routinely treated with synthetic glucocorticoids (sGC) between 24 and 34 of weeks gestation to improve neonatal outcome. Animal studies have demonstrated that maternally administered sGC crosses the placenta, affecting fetal hypothalamic-pituitary-adrenal (HPA) development, resulting in changes in HPA axis function that persist throughout life. These changes appear to be modulated at the level of glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) in the brain and pituitary. As the HPA axis interacts with many other physiological pathways, the changes in endocrine function are also sex-specific and age-dependent. Alterations in behavior, particularly locomotion, in animals exposed to sGC in utero have also been demonstrated. Consistent with the finding in animal models, emerging human data are indicating attention deficit-hyperactivity disorder (ADHD)-like symptoms in children exposed to repeated courses of sGC in utero. This behavioral phenotype is likely linked to alterations in dopamine (DA) signaling, suggesting that sGC are able to permanently modify or 'program' this system. Finally, it is emerging that changes in HPA axis function and behavior following antenatal exposure to sGC are transgenerational and likely involve epigenetic mechanisms. A comprehensive understanding of the acute and long-term impact of sGC exposure in utero is necessary to begin to develop recommendations and treatment options for pregnant women at risk of preterm delivery.

Maternal stress and behavior modulate relationships between neonatal stress, attention, and basal cortisol at 8 months in preterm infants

There is evidence that the developmental trajectory of cortisol secretion in preterm infants is altered, with elevated basal cortisol levels observed postnatally through at least 18 months corrected age (CA). This alteration is possibly due to neonatal pain-related stress. High cortisol levels might contribute to greater risk of impaired neurodevelopment. Since maternal factors are important for the regulation of infant stress responses, we investigated relationships between infant (neonatal pain-related stress, attention, cortisol) and maternal (stress, interactive behaviors) factors at age 8 months CA. We found that interactive maternal behaviors buffered the relationship between high neonatal pain-related stress exposure and poorer focused attention in mothers who self-reported low concurrent stress. Furthermore, in preterm infants exposed to high concurrent maternal stress and overwhelming interactive maternal behaviors, higher basal cortisol levels were associated with poor focused attention. Overall, these findings suggest that maternal factors can influence the cognitive resilience at 8 months of preterm infants exposed to early life stress.

Fetal programming of temperamental negative affectivity among children born healthy at term

The fetal programming hypothesis suggests that an adverse in utero environment, reflected in small body size at birth, has life-long effects on different physiological systems that may affect both health and behavior. We explored whether fetal growth was associated with biologically based temperamental outcomes (negative affectivity scales, the CBQ) among 5(1/2)-year-old children (n = 416) born healthy at term (gestational weeks 37-42). In line with the hypotheses, small body size at birth (thinness measured by ponderal index, kg/m(3)) was related to increased negative affectivity and its subscales: anger-, discomfort-, and sadness-proneness in childhood. Longer length at birth was predictive of higher levels of child anger- and sadness-proneness. Length of gestation moderated the associations of weight and length at birth with negative affectivity. The results suggest that the biological basis of temperament may be subjected to antenatal environmental influences, and that the mechanisms, proposed to be related to fetal glucocorticoid environment, may operate even within the normal range of term birth.

Prenatal dexamethasone exposure, postnatal development, and adulthood prepulse inhibition and latent inhibition in Wistar rats

Prenatal stress is an important risk factor in schizophrenia, and the aetiological factors mediating this relationship are central to the neurodevelopmental hypothesis of schizophrenia. The glucocorticoid receptor (GR) agonist dexamethasone (DEX) is commonly prescribed for prenatal conditions, and results in GR activation, which is part of the stress response. To investigate animal evidence for whether prenatal DEX leads to development of schizophrenia-like phenotypes, Wistar rats were prenatally exposed to DEX (0.1mg/kg/day) between the gestational days 15 and 21, and tested in two paradigms known to be disrupted in schizophrenia patients: prepulse inhibition (PPI) and latent inhibition (LI). A cross-fostering design was used to allow dissociation of any direct prenatal effects on offspring from effects dependent on DEX exposure of the rearing dam. Pup birth weight was reduced by prenatal DEX treatment. DEX-treated dams demonstrated increased pup-directed behaviour. There were additive effects of prenatal DEX treatment and DEX treatment of rearing dam in terms of reduced body weight in adulthood. In one of two replications, PPI was increased by prenatal DEX in males only and specific to the highest prepulse intensity. There was no evidence that LI was disrupted by prenatal DEX treatment. This study does not provide support for the hypothesis that prenatal DEX exposure leads to schizophrenia-like deficits in PPI or LI, suggesting that GR prenatal programming is not a mechanism of direct relevance to the neurodevelopmental hypothesis of schizophrenia.

Outcome of fetal cardiac defects

PURPOSE OF REVIEW

The present review summarizes the prenatal and postnatal outcome of cardiac anomalies and sustained arrhythmias diagnosed during fetal life.

RECENT FINDINGS

The outcome of sustained fetal arrhythmias has improved with greater experience using Sotalol for atrial flutter, and digoxin and amiodarone for 1: 1 reciprocating tachycardia. The outcome of fetal conduction system disease secondary to maternal Sjögren's antibodies has noticeably improved with transplacental dexamethasone. The postnatal prognosis for atrioventricular block associated with left atrial isomerism, however, remains very bleak. Assessing the effect of prenatal diagnosis on the outcome of structural defects remains difficult because of the high number of extracardiac anomalies and chromosome defects in this group. Preoperative survival is improved, but postoperative mortality has not improved. One clear advantage of prenatal diagnosis is the selection of fetuses that may benefit from in-utero intervention to limit the progression of their disease or lessen its severity at birth.

SUMMARY

For the most part, postoperative mortality of structural cardiac defects is not significantly improved by prenatal diagnosis. In-utero management of tachyarrhythmias and conduction system disease has improved postnatal outcome, except for the fetus with atrioventricular block and left atrial isomerism.

Cognition- and anxiety-related behavior, synaptophysin and MAP2 immunoreactivity in the adult rat treated with a single course of antenatal betamethasone

We investigated the effects of a single course of antenatal betamethasone on cognition- and anxiety-related behavior and synaptophysin and microtubule-associated protein 2 (MAP2) immunoreactivity in the adult rat hippocampus. On d 20 of gestation, pregnant rats were injected with either 1) 170 microg/kg body weight of betamethasone ("clinically equivalent dose," equivalent to 12 mg twice, 24 h apart); 2) half this dose; or 3) vehicle. Cognition- and anxiety-related behavior of the offspring was analyzed at an age of 5 mo using the Morris water maze, object recognition task, and open field test. Subsequently, synaptophysin and MAP2 immunoreactivity were measured in the hippocampus. We report no detrimental effects of antenatal betamethasone on cognition- and anxiety-related behavior and synaptophysin immunoreactivity in the adult rat. On the other hand, MAP2 immunoreactivity was decreased by betamethasone in males, suggesting a permanent impairment in the hippocampus. Interestingly, the lower dose appears to have less influence in terms of growth restriction, known to be associated with an increased risk of disease in adulthood. Further research might elucidate whether the betamethasone effect on hippocampal neurons persists later in life and could affect the aging process increasing the risk for neuropathology of the adult.

Antenatal betamethasone treatment has a persisting influence on infant HPA axis regulation

OBJECTIVE

To examine the consequences of antenatal betamethasone (AB) exposure on postnatal stress regulation.

STUDY DESIGN

Fourteen AB exposed infants born at 28-30 weeks' gestation were assessed in the NICU during postnatal week 1 and at 34 weeks postconception. Nine infants born at 34 weeks gestation without AB treatment were evaluated as a postconceptional age comparison group. Salivary cortisol, heart rate, and behavior were measured at baseline and in response to a heelstick blood draw.

RESULTS

Repeated measures ANOVAs revealed that both groups displayed an increase in heart rate and behavioral distress in response to the stressor. The cortisol response, however, was blunted in AB-treated infants at both assessments.

CONCLUSION

AB treatment has consequences for hypothalamic-pituitary-adrenal (HPA) axis regulation that persist for at least four to six weeks after birth, indicating that studies of long-term effects are warranted.

Three weekly courses of betamethasone administered to pregnant baboons at 0.6, 0.65, and 0.7 of gestation alter fetal and maternal lymphocyte populations at 0.95 of gestation

The hypothalamic-pituitary-adrenal (HPA) axis plays a major role in the communication between the immune and neuroendocrine systems. Glucocorticoids are potent immunomodulatory hormones. In the present study, we evaluated the effect of three weekly courses of betamethasone, administered to pregnant baboons at 0.6, 0.65, and 0.7 of gestation, on maternal hematological parameters during treatment, maternal and fetal hematological parameters and lymphocyte populations at 0.95 of gestation, and fetal lymphoid organs and placental structure. Each weekly betamethasone course resulted in decreased granulocytes and increased lymphocytes and monocytes in maternal circulation (by percentage, p < 0.05). The percentage and absolute number of CD8+ T-cells in the maternal circulation were lower and CD4+ T-cells higher (p < 0.05) in treated pregnant animals at 0.95 gestation. The percentage of proliferating CD3- CD8+ cells was lower in blood obtained from the fetal heart of betamethasone-treated animals. In the betamethasone group, the number of CD8+ T-cells and NK cells were elevated and the number of T and CD4+ T-cells were reduced in fetal heart blood compared with the umbilical vein blood. The number of placental macrophages (CD68+ cells) per visual field in betamethasone-treated and control animals were not different. Taken together, our data show that betamethasone treatment of pregnant females with no indication of preterm labor affects some components of the fetal and maternal immune system, altering the maternal CD4+/CD8+ ratio and absolute number of fetal NK cell and maternal CD8+ T-cell.